Device for simultaneously controlling a plurality of variable resistors

ABSTRACT

A bearing having spherical bearing surface is attached to an opening formed at the center of the top wall of a casing. The bearing rotatably receives a spherical body having a control shaft which extends through the center of the spherical body and is securely fixed thereto. A plurality of outer resistors is arranged on the bottom wall of the casing in a frame-like form and a plurality of arcuate shaped inner resistors is circularly arranged inside of the outer resistors. A pair of intersecting slidable members each having an elongated guide slot and an outer contactor at the opposite ends thereof is slidably movable in the casing with the contactors being in slidable engagement with the corresponding outer resistors. A rotary disc having a plurality of inner contactors equal in number to the inner resistors is rotatably supported on the bottom wall of the casing. The lower end of the control shaft slidably extends through the guide slots of the intersecting members. A universal joint operatively couples the lower end of the control shaft to the rotary disc. As the control shaft is inclined in any direction to any tilt angle, the point of contact on each of the two or four outer resistors may be simultaneously controlled in desired proportions. As the control shaft is rotated about its axis with the control shaft being held in the same tilted position, the point of contact on each of the inner resistors may be simultaneously controlled in an equal proportion.

United States Patent Nishioka et al. Nov. 4, 1975 DEVICE FOR SIMULTANEOUSLY CONTROLLING A PLURALITY OF [57] ABSTRACT VARIABLE RESISTORS A bearing having spherical bearing surface is attached [75] Inventors: Matsuo Nishioka; Shunzo Oka, both to an opening formed at the center of the top wall of of Kadoma, Japan a casing. The bearing rotatably receives a spherical [73] Assignee: Masushim Electric Industrial body having a control shaft which extends through the center of the spherical body and is securely fixed Company, Limited, Japan thereto A plurality of outer resistors is arranged on [22] Filed: June 17, 1974 the bottom wall of the casing in a frame-like form and a plurality of arcuate shaped inner resistors is circu- [211 Appl' 480230 larly arranged inside of the outer resistors A pair of intersecting slidable members each having an elon- [52] US. Cl 338/128; 74/471 XY; 200/6 A; gated guide slot and an outer contactor at the opposite 323/80; 338/l27 ends thereof is slidably movable in the casing with the [51] Int. Cl. HOlC 9/02 contactors being in slidable engagement with the cor- [58] Field of Search 338/90, 127, 128, 129, responding outer resistors. A rotary disc having a plu- 338/130, l3 1, I32; 74/47] XY; 200/6 A; rality of inner contactors equal in number to the inner 323/80; 340/384 R, 366 D; 403/383 resistors is rotatably supported on the bottom wall of the casing. The lower end of the control shaft slidably [56] References Cited extends through the guide slots of the intersecting UNITED STATES PATENTS members A universal joint operatively couples the 3,372,359 3/1968 Wilson 338/128 lower end Of 39? Shaft h rqtary A 3 629 775 12/1971 Kindred 1. 338/l28 the Comm Shaft any dlrecno any 3:662:3l3 5/1972 Komatsu 338/90 aflgkh the Point Of Contact each Of the two 3,701,961 10/1972 Kasazimaw 1. 338/12 outer resistors may be simultaneously controlled in de- 3,739,316 6/1973 Tokubo 338/128 sired proportions. As the control shaft is rotated about 3,760,320 9/1973 Oka et al. 338/128 its axis with the control shaft being held in the same 3,795,882 3/1974 TOkUbO r r r 4 4 r r 338/l28 position the point 0f ontact on each f the inner resistors may be simultaneously controlled in an Primary Examiner-Volodymyr Y. Mayewsky equa| proportion, Attorney, Agent, or Firm-Robert E. Burns; Emmanuel J. Lobato; Bruce L. Adams 9 Claims, 6 Drawlng Figures 34b 28c 350 35 B 28b 35b 37 29 I6 240 33 31 1 1 l2 l0 1o 1 1 19 I? r--ll5 1AM A 22 ates 1 t 1 26 l4 I8 230 2'! l0 U.S. Patent Nov. 4, 1975 Sheet 1 0f 2 3,918,021

FIG. I

FIG. 3

26 I4 l8 230 2? lu m m m a M J r \\\\u L\ M S I 2 I .6 l w I t. 2 M O 0\ I 2 2 Ma I 2 2 2 d 9 2 b 9 2 M 7 2 US. Patent Nov. 4, 1975 Sheet 2 of 2 3,918,021

FIG. 4 FIG. 5

FIG. 6

DEVICE FOR SIMULTANEOUSLY CONTROLLING A PLURALITY OF VARIABLE RESISTORS The present invention relates generally to variable resistors, and particularly to a device for simultaneously controlling a plurality of variable resistors.

In a prior art device, a bearing having a spherical bearing surface is attached to an opening formed at the center of the top wall of a casing having side walls. The bearing rotatably receives a spherical body having a control shaft which extends through the center of the spherical body and is securely fixed thereto. Variable resistors of the conventional type are attached to the side walls of the casing in such a manner that their rotary shafts may extend into the casing. Each of the opposed pairs of the variable resistors are interconnected with a bow-shaped elastic connecting member having an axially elongated slot. The lower end of the control shaft is fitted into the axially elongated slots of the connecting members which intersect each other, but do not interfere with each other.

Although the prior art device is useful for applications such as a four-channel phonograph to provide balance control between sound outputs of the respective sound channels, a separate volume control device is needed to control the absolute levels of the sound outputs irrespective of the balance control.

Therefore, the principal object of the invention is to provide an improved device for simultaneously controlling a plurality of variable resistors wherein simultaneous variation in resistance values relative to each other is effected in combination with simultaneous variation in the absolute resistance values without affecting the resistance values relative to each other.

Another object of the invention is to provide an improved device for simultaneously controlling a plurality of variable resistors wherein the variable resistors are arranged in a manner that permits the resistors to be constructed from a single sheet of resistive material.

A further object of the invention is to provide an improved device for controlling a plurality of variable resistors wherein overall size of the device is kept to a minimum.

A still another object is to provide an improved device for simultaneously controlling a plurality of variable resistors wherein the production cost is minimized.

A still further object of the invention is to provide a uniaxial balance and volume control device to facilitate control in the magnitude of the respective sound channels.

Briefly described, the device in accordance with the invention has a casing having a pair of opposing walls. An opening is provided in one of the opposing walls in which a bearing having a spherical inner surface is attached. The bearing rotatably receives a spherical body having a control shaft which extends through the center of the spherical body and is securely fixed thereto. A plurality of outer resistors in strip-like form is arranged on the other wall of the casing in the outer periphery thereof in generally frame-like configuration. A plurality of circularly arranged inner resistors in arcuate form is also arranged on the other wall. A pair of intersecting slidable members each having an elongated guide slot is slidably movable in the casing transversely to the axis thereof and longitudinally to each other. Each of the intersecting members has an outer contactor at the opposite ends thereof which is slidably kept in electrical contact with the outer resistors. One end of the control shaft slidably extends through the guide slots of the intersecting members whereby pivotal movement of the control shaft permits each of the intersecting members to slide transversely to the axis thereof and longitudinally to each other. A rotary disc having a plurality of inner contactors equal in number to the inner resistors is rotatably supported on the other wall of the casing, with the contactors being in slidable contact with the inner resistors. A universal joint is provided to operatively couple the rotary disc with the one end of the control shaft. Rotation of the control shaft about the axis thereof causes the rotary disc to rotate so that the contactors slide in engagement with the corresponding inner resistors.

When the control shaft is inclined to a given tilt angle in any direction, the outer contactors slide in engagement with the corresponding outer resistors in accordance with the angle and direction of the tilted control shaft so that the point of contact on each of the two or four outer resistors is simultaneously controlled in desired proportions. As the control shaft is rotated about its axis with the control shaft being held at the same position, the point of contact on each of the inner resistors will be simultaneously controlled in an equal porportion.

These and other features of the present invention will become apparent as the following description proceeds when taken in conjunction with the accompanying drawings, in which:

FIG. I is a cross-sectional view in elevation of a device in accordance with the invention;

FIG. 2 is a plan view of the device with the top wall of a casing being removed;

FIG. 3 is a plan view of the device with a pair of intersecting slidable members being removed to show a plurality of resistors arranged on the bottom wall of the casing;

FIG. 4 is a plan view of a plurality of resistors constructed from a single sheet of resistive material;

FIG. 5 is an equivalent circuit of the resistors employed in the present invention; and

FIG. 6 is an enlarged perspective view of a universal joint employed in the device of the present invention.

Referring to FIGS. 1-5, a preferred embodiment of the invention will be described. A box-like casing 1 has a top wall and opening 2 therein to which are attached with rivets 3 upper and lower bearings 4 and S which are made of a synthetic resin by molding and which have spherical inner surfaces. A spherical body 6 having a control shaft 7 extending axially through the center thereof is pivotally received in these bearings 4 and 5. Ears 12 of the casing 1 is folded back in order to securely attach the bottom wall to the casing. The casing 1 has on the bottom wall an opening 8 to which is attached a bearing 9. A rotary shaft 10 is rotatably received into the bearing 9 and has a knob ll at the lower end thereof. A disc 13 ofa non-conducting material has an opening at the center thereof in which the upper end of the rotary shaft 10 is securely fitted. On the bottom wall of the casing 1 there is arranged a plurality of outer resistive elements 14 to 17 along the peripheral edges of the bottom wall in a generally rectangular frame-like form and a plurality of inner resistive elements 18 to 21 or arcuate shape circularly arranged inside of the frame-like configuration formed by the outer resistive elements, as best shown in FIG. 3. The outer resistive elements 14 to 17 are interconnected by means of conductive elements 22 to 25 which have legs 22a, 23a, 24a, and 25a formed integrally therewith and extending inwardly to one end of associated inner resistive elements 18 to 21, respectively. It is seen that outer resistive elements 14 to 17 are connected in parallel to the inner resistive elements 18 and 21, respectively. A conductive ring 26 is disposed inside of an area defined by the inner resistive elements 18 to 21 on the bottom wall of the casing 1. An outer conductive framelike element 27 is disposed on the bottom wall of the casing 1 around the outer periphery of the outer resistive elements 14 to 17 with each of the side members being parallel thereto.

A slidable elongated member 28 having an elongated guide slot 280, downwardly flared portions 28b, 28c and upwardly flared portions 28d is provided in the easing 1. Each of the downwardly flared portions 28b, 28c has a pair of interconnected contactors such as brushes 30, 31 and a pair of interconnected contactors 32, 33 on the lower surface thereof which make slidable electrical contact with outer resistive element 15, outer conductive element 27, outer resistive element 17 and outer conductive element 27, respectively. Another slidable elongated member 29 having an elongated guide slot 290, downwardly flared portions 29b, 29c and upwardly flared portions 29d is provided in the easing in such a manner that it intersects the slidable member 28 preferably at right angles. Similarly, each of the downwardly flared portions 29b, 29c has a pair of interconnected contactors (not shown) on the lower surface thereof which make slidable electrical contact with outer resistive element 14, outer conductive element 27, outer resistive element 16 and outer conductive element 27, respectively. The intersecting slidable members 28 and 29 have stepped shoulder portions 28c and 29e respectively along the edge of the respective guide slots 28a and 29a.

An interlocking element 34 of a disc configuration having a pair of inwardly cutaway portions 34a on the opposite sides thereof and an aperture 34b along the axis thereof is slidably received in the guide slots 28a and 29a of the intersecting members 28 and 29. The lower end of the control shaft 7 slidably extends through the aperture 34b of the interlocking element 34.

In accordance with the present invention there is provided a universal joint 35 which comprises an input shaft 350 rotatably coupled by means of spider 35e to a bracket 35c fixed to the lower end of the control shaft 7 and an output shaft 35b rotatably coupled by means of spider 35fto a bracket 35d fixed to the rotary disc 13 (FIG. 6). The input shaft 35a has a rectangular or polygonal cross-section and axially slidably extends into the interior of the output shaft 35!) of a rectangular or polygonal cross-section. This arrangement permits the control shaft 7 to cause sliding movements of the slide members 28 and 29 without effecting rotary movement of the rotary disc 13, while permitting control of the latter without effecting the sliding movements of the former. The rotary disc 13 has on its lower surface four pairs of equally spaced, radially arranged interconnected contactors 36 and 37 to make slidable electrical contact with the inner resistive element 19 (20, 21, 18) and the inner conductive element 26. As best shown in FIG. 5, the outer and inner resistive elements are electrically interconnected. Resistors l and 19 are connected in parallel to each other to a common terminal 36 through contactors 30 and 31, outer conductive element 27 to which inner conductive element 26 is connected electrically by suitable means, and through contactors 36 and 37, the common terminal being connected to the inner conductive element 26. Similarly, the rest of the outer and inner resistive element is connected in the same manner as described above. A plurality of terminals 14a, 15a, 16a, and 17a is provided at each corner of the frame-like resistive elements 14 to 17 to provide connection to external circuitry associated with the respective sound channels with the terminal 36 being common to the external circuit.

When the control shaft 7 is inclined pivotally to a given angle in any direction, the interlocking element 34 will evidently slide along the guide slots 28a and 29a of the respective slidable members 28 and 29. Therefore, the slidable members 28 and 29 are caused to move transversely to the axis thereof and longitudinally to each other. It is appreciated that the intersecting slidable members 28 and 29 singly or simultaneously move in directions perpendicular to each other in accordance with the direction of the control shaft 7 so that the four interconnected pairs of contactors provided on the lower surface of the downwardly flared portions 28b, 28c, 29b, 29c, may follow straight paths in slidable contact with the outer resistive elements 14 to 17 as well as the outer conductive element 27. The simultaneous control of the resistance values of outer resistors 14 to 17 in different proportions is thus effected, with the variation in resistance being dependent upon the tilt angle of the control shaft. The upwardly flared portions 28d and 29d of the slidable members 28 and 29 are in slidable contact with the top wall of the casing 1 so that the slidable members may slide on a two-dimensional plane parallel to the top wall of the casing. The downwardly flared portions 29b, 28c, 29b, and 29c have preferably a predetermined weight in order to provide an inertia-producing effect for smooth movement of the intersecting members 28 and 29.

With the control shaft 7 being held at a given tilt angle in a given direction, the control shaft is rotated about its axis. The rotation of the control shaft is transmitted through the universal joint 35 to the rotary disc 13 so that the four interconnected pairs of contactors on the lower surface thereof may follow a circular path in contact with the inner resistive elements 18 to 21 as well as the inner conductive element 26. This provides simultaneous variation of the magnitude of the inner resistive elements 18 to 21 in an equal proportion while keeping the outer resistive elements 14 to 17 at the given magnitude of resistance determined by the angle and direction of the tilted control shaft. It is appreciated that the outer resistances are only varied in their magnitudes by the direction and tilt angle of the control shaft 7 while the inner resistances are only varied in their magnitudes by the rotation of the control shaft 7 about the axis thereof.

The arrangement as described above is particularly useful for applications such as four-channel stereophonic recording or playback apparatus. The outer resistances thus arranged serve to provide balance control between the respective sound channels wherein the sound levels of the channels are varied simultaneously relative to each other while the inner resistance serve to control the absolute sound levels of the separate channels in an equal proportion.

Since the outer resistors are parallel-connected with associated inner resistors, the variation in the resistance values of the inner resistors, and vice versa, effectively varies the resultant resistance values of the parallel-connected outer and inner resistors. This allows reduction in the number of terminals required for connection to external circuits.

Although the resistive elements may be separated from each other for individual connections to external circuits, this will be disadvantageous from the production standpoint. This invention thus permits the outer and inner resistive elements to be constructed from a single sheet of resistive material, for example, by punching it out into a shape, as illustrated in FIG. 4, having a generally rectangular frame-like outer portion, circularly spaced arcuate shaped inner portions and four legs extending from each corner of the framelike portion inwardly to each of the arcuate shaped portions. The four legs are covered with the conductive elements 22 to 25. The resistive elements are thus produced in a manner that tends to reduce the production cost and the overall size of the device.

What is claimed is:

1. in a device for simultaneously controlling a plurality of variable resistors, including a casing having a pair of opposed insulating members, a control shaft pivotally supported by and extending through one of said opposed members, a pair of intersecting slide members each having an elongated guide slot and being slidably movable mutually perpendicularly to each other, one end of said control shaft slidably extending through the guide slots of said intersecting slide members, the improvement in combination therewith which comprises an insulating rotary member rotatably supported on the other member of said casing at a predetermined spacing therefrom, a universal joint coupling the axis of said rotary member with said one end of said control shaft, said variable resistors including a plurality of elongated outer resistive elements in a rectangular frame-like form on the said other member and a plurality of first electrical contact elements equal in number to said outer resistive elements at the opposite ends of each of said intersecting slide members and in slidable electrical contact with the corresponding outer resistive element, and a plurality of inner arcuate shaped resistive elements circularly arranged on the said other member in opposed relation to said rotary member and a plurality of second electrical contact elements equal in numher to said inner resistive elements and carried by said rotary member in slidable electrical contact with the corresponding inner arcuate shaped resistive element, said outer resistive elements being electrically interconnected to each other, and each of said outer resistive elements being electrically connected to respective ones of said inner resistive elements.

2. The improvement as claimed in claim I, wherein each of said outer resistive elements is further connected to an external terminal.

3. The improvement as claimed in claim 1, wherein said outer and inner resistive elements are connected conductively.

4. The improvement as claimed in claim 1, wherein said first and second electrical contact elements are connected to a further external terminal.

5. The improvement as claimed in claim I, wherein each of said intersecting elongated member has at each end thereof a side member of a predetermined weight slidably in contact with said one of the opposed walls and slidably movable on said outer resistive element.

6. The improvement as claimed in claim 1, further comprising a rectangular frame-like conductive element adjacent said outer resistive elements, said first electrical contact element providing electrical connection between said conductive element and the corresponding outer resistive element.

7. The improvement as claimed in claim 5, further comprising an annular conductive element adjacent said inner resistive elements, said second electrical contact element providing electrical connection between said annular conductive element and the corresponding inner resistive element.

8. The improvement as claimed in claim 5, wherein said rectangular frame-like conductive element are connected to a common terminal.

9. The improvement as claimed in claim 1, wherein said universal joint comprises an input shaft having a polygonal cross-section and an output shaft having a polygonal cross-section, said input shaft being rotatably coupled through a first spider to the lower end of said control shaft and axially slidably extending into said output shaft, said output shaft being rotatably coupled through a second spider to said rotary disc.

I t t 1F t 

1. In a device for simultaneously controlling a plurality of variable resistors, including a casing having a pair of opposed insulating members, a control shaft pivotally supported by and extending through one of said opposed members, a pair of intersecting slide members each having an elongated guide slot and being slidably movable mutually perpendicularly to each other, one end of said control shaft slidably extending through the guide slots of said intersecting slide members, the improvement in combination therewith which comprises an insulating rotary member rotatably supported on the other member of said casing at a predetermined spacing therefrom, a universal joint coupling the axis of said rotary member with said one end of said control shaft, said variable resistors including a plurality of elongated outer resistive elements in a rectangular frame-like form on the said other member and a plurality of first electrical contact elements equal in number to said outer resistive elements at the opposite ends of each of said intersecting slide members and in slidable electrical contact with the corresponding outer resistive element, and a plurality of inner arcuate shaped resistive elements circularly arranged on the said other member in opposed relation to said rotary member and a plurality of second electrical contact elements equal in number to said inner resistive elements and carried by said rotary member in slidable electrical contact with the corresponding inner arcuate shaped resistive element, said outer resistive elements being electrically interconnected to each other, and each of said outer resistive elements being electrically connected to respective ones of said inner resistive elements.
 2. The improvement as claimed in claim 1, wherein each of said outer resistive elements is further connected to an external terminal.
 3. The improvement as claimed in claim 1, wherein said outer and inner resistive elements are connected conductively.
 4. The improvement as claimed in claim 1, wherein said first and second electrical contact elements are connected to a further external terminal.
 5. The improvement as claimed in claim 1, wherein each of said intersecting elongated member has at each end thereof a side member of a predetermined weighT slidably in contact with said one of the opposed walls and slidably movable on said outer resistive element.
 6. The improvement as claimed in claim 1, further comprising a rectangular frame-like conductive element adjacent said outer resistive elements, said first electrical contact element providing electrical connection between said conductive element and the corresponding outer resistive element.
 7. The improvement as claimed in claim 5, further comprising an annular conductive element adjacent said inner resistive elements, said second electrical contact element providing electrical connection between said annular conductive element and the corresponding inner resistive element.
 8. The improvement as claimed in claim 5, wherein said rectangular frame-like conductive element are connected to a common terminal.
 9. The improvement as claimed in claim 1, wherein said universal joint comprises an input shaft having a polygonal cross-section and an output shaft having a polygonal cross-section, said input shaft being rotatably coupled through a first spider to the lower end of said control shaft and axially slidably extending into said output shaft, said output shaft being rotatably coupled through a second spider to said rotary disc. 